Docker Hub has a section in the “Build configurations” section to specify build environment variables:

The problem is that the value of the variable appears in clear text, which makes this mechanism unsuitable for variables holding sensitive information (e.g. passwords).

I was thinking in something similar to the secrets mechanism in GitHub which allow to define variables which value is seen only one time (in the moment of creating them) but can be latter used in GitHub Actions as many times as you want.

Is there a way to define build variables in Docker Hub without showing the value in the interface? Or any other suitable workaround?